Atari 2600 voltage regulator troubleshooting and replacement

There’s not much that goes wrong with an Atari 2600. Virtually every problem I’ve ever found with them has to do with the electrical path. That means the power supply, the power switch, or the voltage regulator. Outside of those three parts, I’ve never seen a problem with one. Let’s talk about the Atari 2600 voltage regulator and troubleshooting the rest of the internal electrical path.

Is the problem the Atari 2600 voltage regulator?

The 7805 voltage regulator in the Atari 2600 is more failure prone than the other solid-state components. It’s not a bad part, but it runs hot and doesn’t age as well as its custom chips.

If your Atari 2600 won’t power on and display and you’ve verified the power supply is good or replaced it and also verified the TV connection, it’s easy to jump to the conclusion it’s the voltage regulator. And you’ll probably be right about as often as you’re wrong. I won’t blame you for replacing the voltage regulator regardless. It’s 40 years old at this point, well past its use-by date. A newer one will run cooler and more reliably.

But I like to know whether I have another problem. So, after you open it up, here’s how to test it. All you need is a good power supply and a multimeter to test, and a soldering iron and solder to repair it.

Checking voltages

Once you have the motherboard out, plug the power supply in and turn the unit on. Don’t worry, this is all low-voltage work here. You’ll see no more than 15 volts DC.

Touch the black probe of your multimeter to the metal shield around the cartridge port. Touch the red probe to the pins on the power switch on the left side of the board. You should see voltage on both sides of the switch. Ideally it’s 9-10 volts, but if there’s a problem, you may see 15 volts.

If you don’t see voltage on both sides of the switch, you have a power switch issue. You may have other issues, but you need to start with the power switch. More on that in a minute.

If the switch is good, move on to the capacitor. There’s a huge capacitor on the left side of the board with two leads on it. Touch the red probe to the pin pointing away from the arrow on the capacitor. If you see voltage there, the power switch works. If you see 15 volts, the voltage regulator probably isn’t working.

Finally, move on to the 7805 voltage regulator itself. It’s a small black integrated circuit with three pins on one side, and a screw holding it to the board on the other. If it’s working right, you should see approximately 9-10 volts on one pin, 0 volts on the middle pin, and approximately 5 volts on the other pin. By approximately, I mean it should be within about .15 volts. Any significant difference larger than that indicates a bad voltage regulator.

Fixing the Atari 2600 power switch

Turn the system off and remove power, then spray some contact cleaner into the switch and flip the switch on and off about 50 times. These switches tend to gum up over the years, but the combination of contact cleaner and working the switch back and forth will frequently free it back up.

Replacement switches are available, but they tend to be expensive. Here’s some good advice on disassembling and rebuilding switches if necessary.

Replacing the Atari 2600 voltage regulator

Atari 2600 voltage regulator
Here’s my Atari 2600 voltage regulator after I replaced it. Even if you’re not very experienced with electronics repair, the swap should take less than 30 minutes.

If you need to replace your voltage regulator, or just want to as a precaution, it’s a fairly easy repair. First, remove power of course.

The 7805 is readily available and cheap on Ebay. I paid less than $2 for a package of 10, shipped. I’ll use them eventually so I didn’t mind. 10 may be more than you need, but it’s hard to argue with two bucks.

First, remove the screw holding the voltage regulator to the board and set it aside. Don’t lose it, as you’ll need to reattach it when you’re done to keep the new 7805 cool.

Replacing a 7805 is easy work if you’ve done board-level repairs before. If you haven’t, and don’t have a lot of desoldering equipment, the easiest way to remove the 7805 is to bend it straight up, then snip off the legs as close to the regulator as possible. Leave a generous length of pin there to grab. Heat up the joint from the underside of the board with your soldering iron and grasp the other end of the pin with some needle-nose pliers. When the joint melts, pull the pin out.

You’ll find some very old heat sink compound on the board where the old regulator used to sit. Clean that off with a bit of alcohol and a cotton swab. Isopropyl alcohol is ideal for this. Here’s why. Apply a sesame seed-sized dab of fresh heat sink compound to the board where the old compound was. If you don’t have any heat sink compound, a bit of lubricating grease will work. It doesn’t take much.

Take your new 7805 and stick it into the holes where the old one came out. Bend the regulator down onto the board and check the fit. You may have to play a bit with the bend to get it to fit. Replace the screw. Flip the board over and solder the three pins into place. Use a bit of flux to keep your dwell time reasonable. It should take less than 10 seconds per pin to get a good solder joint. Clean up the connections with some alcohol and a cotton swab when you’re done.

Hook the board up to a power supply and to a TV to ensure you’re getting a picture, then reassemble. Congratulations on your repair, and enjoy your 2600.

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